Alpeed g



(No Model.)

' A. G. HOLCOMBE.

MBGHANIGAL TELEPHONE.

' No. 306K316. Patented Oct. 14, 1884.

Fig/5 UNITED STATES FFIICE FATEN'r ALFRED G; HOLOOMBE, OF NEW YORK, N.Y., ASSIGNOR TO THE EQUITABLE ELECTRIC COMPANY, OF SAME PLACE.

MECHANICAL TELEPHONE.

SPECEPICATEON forming part of Letters Patent No. 306,616, dated October14, 1884.

v i Application filed June 4, 1884. (No model.)

To all whom, it may concern Be it known that I, ALFRED G. HOLOOMBE,

a citizen of the United States, and a resident of New York, county andState of New York, have invented certain new and useful Improvements inMechanical Telephones, of which the following is a specification.

In mechanical telephones heretofore made the end of the line-wire issecured directly to the diaphragms, and dependence is placed on thestrength of the diaphragms, which in some cases have been re-enforced tohold said linewire under tension. It is necessary, to obtain goodresults,that the line be stretched as ti ghtly as possible,so as totransmit the sounds in a perfect manner, and this desideratum I attainby stretching the line-wire between suitable supports or bracesindependent of the sound receiving or transmitting diaphragms, which areby suitable means adjustably connected to the ends of the line-wireafter it is erected, subjected to the maximum tensional strain it willbear. The diaphragms, which are fastened to or form the covers of thecases in which the ends of the'line-wires are supported un dertension,are drawn at their centers toward the ends of the line-wires bymeans of screws, by which they are submitted to the proper 1 strain toproduce perfect results when the instruments are used either astransmitters or receivers. v

A simple and effective way for holding the line-wire under tensionindependent of the diaphragms consists in arranging in thetelephone-cases a series of transverse wires, or one piece of wirepassed several times through the sides of the case so as to cross at ornear the center thereof, at which part of these transverse wires the endof the line-wire is secured by means of a suitable clamping device, sothat the tension strain of theline-wire applies a transverse strain tothem, but to describe my invention more particularly I will now refer tothe accompanying drawings, in which- Figure 1 is a longitudinal centralsection of my improved mechanical telephone. Fig. 2 is atransversesection of the same on the line as 00, looking toward the diaphragm.Fig. 3 is a perspective view with the diaphragm and cover removed, andFig. 4 is a perspective view of the diaphragm and cover.

The case of the instrument is composed of the body a, shown cylindricalin form, but

which may be of any desired shape, the base I), to which the body a issecured, and the ring 0, made so as to fit over the open end of the bodya.

Through holes in the body a is passed the wire d, in the manner shown,so that the transverse parts thereof are stretched across the inside ofthe body in pairs, leaving a space between them at the center of thebody.

Separate pieces of wire stretched across the body a, and secured theretoin any suitable manner, may be used instead of one piece passed back andforth as shown, and the number of sections crossing the interior of thecase may be varied as desired. The end of the line-wire e is secured inan eye formed on the boltf,which is provided with a flange, f, and thefront end of which is screw-threaded, so as to fit in the nut g. Thisnut g is provided with a series of taper projections, g, on itsperiphery, which extend some distance from its face, and are so arrangedas to fit in the outer angles formed by the crossing of the transverseparts of the wire (I, in such a manner as to draw said wires somewhattogether, and securely hold them in position when the central parts ofthe wire are clamped between the face of the nut g and the flange f ofthe bolt f. The line-wire e is by this means securely fastened to thetransverse supportingwvires d, and. can be stretched to any desiredextent after the case is secured in position, independent of thediaphragm, as shown in Fig. 3.

To the inside of the ring 0 of the cover, the side flange of whichcovers the parts of the wire d which are on the outside of the case a,is secured the diaphragm h by its edges being clamped between the flatring 0 'and the flat part of the ring a, a suitable cement being usedfor this purpose 5 or they may be fastened together by means of rivets.After the diaphragm h, with the ring 0, is placed over the open end ofthe case a, the center of the diaphragm is connected to the boltf bymeans of the small screw i, which is passed through it into a tappedhole formed in the end of the bolt f, thus providing a simple means bywhich the diaphragm may be adjustably stretched, and subjected to theright strain to produce the best results, and this, too, after thelinewire is erected in position under the proper tension, and withoutinterfering with or decreasing the tension of the line-wire.

IVhat I claim, and desire to secure by Letters Patent, is-

1. In a mechanical telephone, the combination of a line-wire secured andpermanently held under tension with a diaphragm independent thereof, butadjustably connected at its center tothe end of the line-wire, substalrtially as and for the purpose set forth.

2. In a mechanical telephone, a line-wire secured at its ends undertension to transverse wires in the case of theinstrun'ients, incombination with a diaphragm connected to the end of the line-wire, orto the central parts of the transverse wires, substantially as and forthe purpose set forth.

8. In combination, an open-end case, a series of transverse wiresstretched across the interior thereof, a bolt to which the line-wire isattached, and a nut fitted on the end of the bolt, so as to connect thesame firmly to the center of the transverse wires, substantially as setforth.

4. In combination, the case a, transverse wire (I, bolt f, nut g,provided with projections g, diaphragm h, and adjusting'screw '5,substantially as set forth.

5. As a new means for holding a mechani cal telephone line-wire undertension, the case a, the wire d, passed through the sides andtransversely across the interior thereof, and a clamping device, bywhich the line-wire is con nected to the centers of the transverse partsof the wire (I, in combination, substantially as set forth. r

In witness whereof I have hereunto set my hand at New York, county andState of New York, this 19th day of May, 1884.

ALFRED G. HOLGOMIIP].

IVitness es:

ALFRED Snnoroon, J. M. PENDLETON.

